Modular lighting refers to modules that can be assembled in order to obtain large lighting devices of various sizes and shapes. Each lighting module has several light elements, e.g. RGB LEDs. In addition to the flexibility in adapting the size and shape of such modular lighting applications, e.g. to the available space where the modular lighting application is to be installed or due to other reasons, such modular lighting applications may be used to visualize lighting patterns, including still and moving images and light effects, on a screen that may have a size and a shape that in general deviates from standard rectangular liquid crystal display (LCD) devices. Particularly two-dimensional lighting modules are typically referred to as lighting tiles, or simply tiles. Such a lighting tile may have various polygonal shapes, such as for example a square, triangle or pentagon shape. The lighting tiles are not limited to two-dimensional shapes but may have a three-dimensional shape, such as a cube or a pyramid.
The shape and size of the lighting system can be changed by adding, removing and relocating lighting tiles. Obviously, by varying the number of tiles in the system, the power demand will vary as well. A user employing only a small number of lighting tiles is most likely reluctant to buy a very powerful and expensive power unit dimensioned for a system comprising a high number of lighting tiles which he may never use to the full. Another issue with such a single power unit solution is that the internal wiring of the lighting tiles would all have to be dimensioned for a load in accordance with the maximum capacity of the single power unit.
The optimal solution to this would be to distribute mains power among the tiles and provide each of the tiles with its own power converter fulfilling the power demands of that specific tile. This would have many advantages, one being that no external power unit is needed which would simplify the system considerably. Another advantage would be that, with each tile having a mains power converter, such a distributed power supply is auto-scaling by itself avoiding the question of which capacity a single external power unit should have. The distribution of mains power among the tiles is, however, prohibited due to safety regulations. Therefore, large systems of lighting tiles have to be powered by a plurality of power units. One lighting system of this kind is disclosed in WO 2007/069130. In that prior art system, the lighting tiles have an internal wiring which make the tiles easy to fit since the rotational orientation of each tile relative to the neighboring tiles is non-essential. In that document one lighting system is mentioned where one power unit is capable of powering up to 10 tiles which means that for more advanced arrangements a considerable number of power units are necessary.